Primary Sources Of Food Contamination|Source Of Food Contamination:

Primary Sources Of Food Contamination|Source Of Food Contamination:-

Food contamination means entry of micro-organism(Mos) to food from external source.Contamination usually brings undesirable Mos in food,illness and health hazard can occurs after the injection of food contaminated with and spoilled by pathogenic Mos.They may contain either the invagic(to penetrate the tissue by itself)mos or their toxins(poison)or both.The source of food contamination with mos may be various and also the level of contamination or load of microbial contamination may differ according to source.The primary source of food contamination are:

• Green plants and fruits
• Animals
• Sewages
• Air
• Water
• Food utensils
• From the food handlers

Green plants and fruits:-

Green plants and food are inhibitat by different micro-organism on their surface,as their natura flora.The natural flora of plants varies but usually include species of Pseudomonas,Alcaligenes,Flavobacterium,Micrococcus,Polyform and Latic acid bacteria(LAB).Bacillus species and yeast or mold may alsobe present.Exposed surface of plants becomes contaminated from soil,water sewage,air and animals.so,that mos from these sources are added to natural flora.

Some fruits may posses vibal mos on their interior.For example normal healthy tomatoes have been shown to contain Pseudomonas,Polyform,Micrococcus,Flavobacterium,Corynebacterium and yeast have been found inside undamaged fruits.Organism have also been found in healthy root and other parts of vegetables.

Animals:-

Like plants,animal may be the source of food contamination as they posses many different kinds of mos as their normal flora on their body surface.The food may get contaminated with mos from their skin flora,the flora of respiratory track,the flora of intectional track.The skin of many meat animals may be the source of Micrococci,Staphylococci and Streptococci,Staphylococci may come from respiratory track and may contaminate the final raw products.The flaecal contaminated product may contain many interic mos including Salmonella.eggs are frequently associated with the case of Salmonellsis(Disease cause by Salmonella).Many of the infectious disease like Brucella,Mycobacterium,Coxiella,Listeria,Campylobacter,Enteropathogenic E.coli as well as others parasites.Viruses may contaminate differents food products and are potential source of pathogens.Indirectly insects and birds may cause mechanical damage to fruits and vegetables and may introduced mos and open the way for a microbial spoilage.

Sewage:-

When untreated domastic sewage is use to fertilize plants crops, there is likelyhood that raw plant foods will be contaminated with organism,either spoillage causing or pathogenic.The most common encounter organism in sewage include pathogenic organism that causes Gastro-enteristis.In addition to the pathogens,coliform,anaerobes,Enterococci and other instentinal bacteria and viruses can contaminated food from these source.Natural water sources contaminated with sewage may contribute their mos to the sea food.

Treated sewage going in to soil or in to water also contribute mos,however the count may be low as compared to the raw sewage.

Soil:-

Soil contain a varities of mos.these organism may contaminate the surface of growing plants as well as surface of roaming animals over the land soil dust containing many mos may get trapped by air current as well as soil particles may be carried out by running water and may be the possible source of food contamination.The soil is important source of heat resistant spore forming bacteria.Bacterial genera like Bacillus,Closteridium,Enterobacter,E.coli,Micrococcus,Alcaligenes,Flavobacterium,Chromobacterium, Pseudomonas,Proteus,Streptococcus,Leuconostuc(Lactic acid fermentation) and Acetobacter as well as some actinomycetes,yeast and mold may be present in soil.

Water:-

Natural water contain not only their natural flora but also mos from soil and possibly from animals or from sewage,if contaminated.Surface water in river and stream and stored water in lakes or large ponds generally contain significant amount of mos.Incontrast ground water have passed through layer of rocks and soil to a definate level and hence most of the mos as well as greater part of suspended paticles have been remove and may posses considerabilly very few mos.the chief kind of bacteria in natural water are species of Pseudomonas,Chromobacterium,Proteus,Micrococcus,Streptococcus,Enterbacter,E.coli etc.But Streptococcus,Enterobacter and E.coli are the most contaminant of water rather than the natural flora.

Contamination of food may comes from water used as ingradients for washing of food,cooling of food,for manufacturing some kinds of food like ice-cream.

Air:-

Disease causing organism especially those causing respiratory infection,spread among the employees by air or the food product may become contaminated.Actually,air doesnot contain natural floraas mos will not get their suitable environment (i.e.lack of sufficient moisture and nutrients).Direct rays from the sun may kill mos suspended in air and hence,reduced their count.However,mos may get into through dust particles,dry soil,spray from stream,lacks,ponds,oceans as well as drop let of moisture from coughing ,sneeging,talking etc.Organism like molds and various spore forming bacteria(resistant to dessication)will survive longestperiod in air.

Plant organism from fodder,silage may also contaminate the air,organism most commonly found in air are those of spore forming Bacillus,Closteridium,Molds and cells of some gram positive non spore forming bacteria as wellas yeast.

Food handlers and food utensils:-

Food may get, contaminated withmos from the equipments or utensils as well as from the hands of food handlers during handling and processing of food.Harvesting tools,containers,slaughtering,knifes,grinders etc are important source of microbial contamination.simillarly,personal hygenic is very important during food processing as nasal cavity,mouth,skin,respiratory tract etc.serves as important source for contaminating microbes.

Note:Polyform-E.coli,Enterobacter,Klebesilla,Citrobacter.

Reference:-

1. WC, Frazier and Westhoff DC. Food Microbiology. Third Edition. New Delhi.: Tata McGraw-Hill Publishing Company Limited, 1986.

   2.JM, Jay. modern Food microbiology. third edition. New delhi: CBS publication, 1987